include
using namespace std;
int main() {
int x,y,i,n;
cin>>x>>y;
if(((x>10000)||(y>10000))||(x<0||y<0))
exit(1);
else if((x==y)&&(x%2==1))
{
n=x+2*(x-1);
cout<<n;
}
else if((x==y)&&(x%2==0))
{
n=2*x;
cout<<n;
}
else if(((x%2==0)&&(y%2==0))&&(x-y==2))
{
n=2*x-2;
cout<<n;
}
else if(((x%2!=0)&&(y%2!=0))&&(x-y==2))
{
n=2*x-3; cout<<n;
}
else
cout<<"No Number";
}